总结一下利用Jedis连接redis连接不上的解决办法

1.先查看防火墙状态
firewall-cmd --state
2.停止防火墙
systemctl stop firewalld.service
3.禁止firewall开机启动
systemctl disable firewalld.service

防火墙的基本使用
CentOS7使用firewalld打开关闭防火墙与端口
1、firewalld的基本使用
启动： systemctl start firewalld
关闭： systemctl stop firewalld
查看状态： systemctl status firewalld
开机禁用 ： systemctl disable firewalld
开机启用 ： systemctl enable firewalld

2.出现以下异常

Exception in thread "main" redis.clients.jedis.exceptions.JedisConnectionException: java.net.ConnectException: Connection refused: connect
    at redis.clients.jedis.Connection.connect(Connection.java:207)
    at redis.clients.jedis.BinaryClient.connect(BinaryClient.java:93)
    at redis.clients.jedis.Connection.sendCommand(Connection.java:126)
    at redis.clients.jedis.Connection.sendCommand(Connection.java:121)
    at redis.clients.jedis.BinaryClient.ping(BinaryClient.java:106)
    at redis.clients.jedis.BinaryJedis.ping(BinaryJedis.java:195)
    at practice.RedisJava.main(RedisJava.java:13)
Caused by: java.net.ConnectException: Connection refused: connect
    at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
    at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at redis.clients.jedis.Connection.connect(Connection.java:184)
    ... 6 more

3.防火墙检查完后，如果还是出现上述问题，说明redis还有地方需要配置，redis默认是只有本机可以访问的，想要远程访问需要修改redis.conf配置文件。
进入redis.conf目录，并使用vi命令打开，找到bind那行修改后，wq保存退出，重启redis-server。

bind 后加的是允许访问的ip
bind 127.0.0.1代表只有本机可以访问，可以将允许访问的ip加入，也可以直接注释掉这一行，这样所有机器都可以访问。

4.解决上述问题后出现的新问题：DENIED Redis is running in protected mode

Exception in thread "main" redis.clients.jedis.exceptions.JedisDataException: DENIED Redis is running in protected mode because protected mode is enabled, no bind address was specified, no authentication password is requested to clients. In this mode connections are only accepted from the loopback interface. If you want to connect from external computers to Redis you may adopt one of the following solutions: 
1) Just disable protected mode sending the command 'CONFIG SET protected-mode no' from the loopback interface by connecting to Redis from the same host the server is running, however MAKE SURE Redis is not publicly accessible from internet if you do so. Use CONFIG REWRITE to make this change permanent. 
2) Alternatively you can just disable the protected mode by editing the Redis configuration file, and setting the protected mode option to 'no', and then restarting the server. 
3) If you started the server manually just for testing, restart it with the '--protected-mode no' option. 
4) Setup a bind address or an authentication password. NOTE: You only need to do one of the above things in order for the server to start accepting connections from the outside.
    at redis.clients.jedis.Protocol.processError(Protocol.java:127)
    at redis.clients.jedis.Protocol.process(Protocol.java:161)
    at redis.clients.jedis.Protocol.read(Protocol.java:215)
    at redis.clients.jedis.Connection.readProtocolWithCheckingBroken(Connection.java:340)
    at redis.clients.jedis.Connection.getStatusCodeReply(Connection.java:239)
    at redis.clients.jedis.Jedis.set(Jedis.java:121)
    at roy.redis.test.Test.init(Test.java:13)
    at roy.redis.test.Test.main(Test.java:8)

报错信息很长，但是主要是说redis开启了protected mode，这也是Redis3.2以上版本加入的新特性，开启保护模式的redis只允许本机登录，同样设置在配置文件redis.conf中，如图
这样基本上就能解决问题了，让我们启动redis

下面是测试代码

package com.xzt.redios.test;

import redis.clients.jedis.Jedis;

public class RedisTest {
	public static void main(String[] args) {
	//第一参数是你redis
		Jedis jedis = new Jedis("192.168.25.122",6379);
		System.out.println(jedis.ping());
	}
	

}

运行结果
这样就成功连通我们的redis啦